src/queue_internal.h

   1 /*
   2  * Copyright (c) 2008-2013 Apple Inc. All rights reserved.
   3  *
   4  * @APPLE_APACHE_LICENSE_HEADER_START@
   5  *
   6  * Licensed under the Apache License, Version 2.0 (the "License");
   7  * you may not use this file except in compliance with the License.
   8  * You may obtain a copy of the License at
   9  *
  10  *     http://www.apache.org/licenses/LICENSE-2.0
  11  *
  12  * Unless required by applicable law or agreed to in writing, software
  13  * distributed under the License is distributed on an "AS IS" BASIS,
  14  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  15  * See the License for the specific language governing permissions and
  16  * limitations under the License.
  17  *
  18  * @APPLE_APACHE_LICENSE_HEADER_END@
  19  */
  20
  21 /*
  22  * IMPORTANT: This header file describes INTERNAL interfaces to libdispatch
  23  * which are subject to change in future releases of Mac OS X. Any applications
  24  * relying on these interfaces WILL break.
  25  */
  26
  27 #ifndef __DISPATCH_QUEUE_INTERNAL__
  28 #define __DISPATCH_QUEUE_INTERNAL__
  29
  30 #ifndef __DISPATCH_INDIRECT__
  31 #error "Please #include <dispatch/dispatch.h> instead of this file directly."
  32 #include <dispatch/base.h> // for HeaderDoc
  33 #endif
  34
  35 #if defined(__BLOCKS__) && !defined(DISPATCH_ENABLE_PTHREAD_ROOT_QUEUES)
  36 #define DISPATCH_ENABLE_PTHREAD_ROOT_QUEUES 1 // <rdar://problem/10719357>
  37 #endif
  38
  39 /* x86 & cortex-a8 have a 64 byte cacheline */
  40 #define DISPATCH_CACHELINE_SIZE 64u
  41 #define ROUND_UP_TO_CACHELINE_SIZE(x) \
  42                 (((x) + (DISPATCH_CACHELINE_SIZE - 1u)) & \
  43                 ~(DISPATCH_CACHELINE_SIZE - 1u))
  44 #define DISPATCH_CACHELINE_ALIGN \
  45                 __attribute__((__aligned__(DISPATCH_CACHELINE_SIZE)))
  46
  47
  48 #pragma mark -
  49 #pragma mark dispatch_queue_t
  50
  51 #define DISPATCH_QUEUE_HEADER \
  52         uint32_t volatile dq_running; \
  53         struct dispatch_object_s *volatile dq_items_head; \
  54         /* LP64 global queue cacheline boundary */ \
  55         struct dispatch_object_s *volatile dq_items_tail; \
  56         dispatch_queue_t dq_specific_q; \
  57         uint16_t dq_width; \
  58         uint16_t dq_is_thread_bound:1; \
  59         pthread_priority_t dq_priority; \
  60         mach_port_t dq_thread; \
  61         mach_port_t volatile dq_tqthread; \
  62         uint32_t volatile dq_override; \
  63         unsigned long dq_serialnum; \
  64         const char *dq_label; \
  65         DISPATCH_INTROSPECTION_QUEUE_LIST;
  66
  67 #define DISPATCH_QUEUE_WIDTH_MAX UINT16_MAX
  68
  69 #define DISPATCH_QUEUE_CACHELINE_PADDING \
  70                 char _dq_pad[DISPATCH_QUEUE_CACHELINE_PAD]
  71 #ifdef __LP64__
  72 #define DISPATCH_QUEUE_CACHELINE_PAD (( \
  73                 (0*sizeof(void*) - DISPATCH_INTROSPECTION_QUEUE_LIST_SIZE) \
  74                 + DISPATCH_CACHELINE_SIZE) % DISPATCH_CACHELINE_SIZE)
  75 #else
  76 #define DISPATCH_QUEUE_CACHELINE_PAD (( \
  77                 (13*sizeof(void*) - DISPATCH_INTROSPECTION_QUEUE_LIST_SIZE) \
  78                 + DISPATCH_CACHELINE_SIZE) % DISPATCH_CACHELINE_SIZE)
  79 #endif
  80
  81 DISPATCH_CLASS_DECL(queue);
  82 struct dispatch_queue_s {
  83         DISPATCH_STRUCT_HEADER(queue);
  84         DISPATCH_QUEUE_HEADER;
  85         DISPATCH_QUEUE_CACHELINE_PADDING; // for static queues only
  86 };
  87
  88 DISPATCH_INTERNAL_SUBCLASS_DECL(queue_root, queue);
  89 DISPATCH_INTERNAL_SUBCLASS_DECL(queue_runloop, queue);
  90 DISPATCH_INTERNAL_SUBCLASS_DECL(queue_mgr, queue);
  91
  92 DISPATCH_DECL_INTERNAL_SUBCLASS(dispatch_queue_specific_queue, dispatch_queue);
  93 DISPATCH_CLASS_DECL(queue_specific_queue);
  94
  95 void _dispatch_queue_destroy(dispatch_object_t dou);
  96 void _dispatch_queue_dispose(dispatch_queue_t dq);
  97 void _dispatch_queue_invoke(dispatch_queue_t dq);
  98 void _dispatch_queue_push_list_slow(dispatch_queue_t dq,
  99                 pthread_priority_t pp, struct dispatch_object_s *obj, unsigned int n,
 100                 bool retained);
 101 void _dispatch_queue_push_slow(dispatch_queue_t dq,
 102                 pthread_priority_t pp, struct dispatch_object_s *obj, bool retained);
 103 unsigned long _dispatch_queue_probe(dispatch_queue_t dq);
 104 dispatch_queue_t _dispatch_wakeup(dispatch_object_t dou);
 105 dispatch_queue_t _dispatch_queue_wakeup(dispatch_queue_t dq);
 106 void _dispatch_queue_wakeup_with_qos(dispatch_queue_t dq,
 107                 pthread_priority_t pp);
 108 void _dispatch_queue_wakeup_with_qos_and_release(dispatch_queue_t dq,
 109                 pthread_priority_t pp);
 110 _dispatch_thread_semaphore_t _dispatch_queue_drain(dispatch_object_t dou);
 111 void _dispatch_queue_specific_queue_dispose(dispatch_queue_specific_queue_t
 112                 dqsq);
 113 unsigned long _dispatch_root_queue_probe(dispatch_queue_t dq);
 114 void _dispatch_pthread_root_queue_dispose(dispatch_queue_t dq);
 115 unsigned long _dispatch_runloop_queue_probe(dispatch_queue_t dq);
 116 void _dispatch_runloop_queue_xref_dispose(dispatch_queue_t dq);
 117 void _dispatch_runloop_queue_dispose(dispatch_queue_t dq);
 118 void _dispatch_mgr_queue_drain(void);
 119 unsigned long _dispatch_mgr_queue_probe(dispatch_queue_t dq);
 120 #if DISPATCH_ENABLE_PTHREAD_ROOT_QUEUES
 121 void _dispatch_mgr_priority_init(void);
 122 #else
 123 static inline void _dispatch_mgr_priority_init(void) {}
 124 #endif
 125 void _dispatch_after_timer_callback(void *ctxt);
 126 void _dispatch_async_redirect_invoke(void *ctxt);
 127 void _dispatch_sync_recurse_invoke(void *ctxt);
 128 void _dispatch_apply_invoke(void *ctxt);
 129 void _dispatch_apply_redirect_invoke(void *ctxt);
 130 void _dispatch_barrier_async_detached_f(dispatch_queue_t dq, void *ctxt,
 131                 dispatch_function_t func);
 132 void _dispatch_barrier_trysync_f(dispatch_queue_t dq, void *ctxt,
 133                 dispatch_function_t func);
 134
 135 #if DISPATCH_DEBUG
 136 void dispatch_debug_queue(dispatch_queue_t dq, const char* str);
 137 #else
 138 static inline void dispatch_debug_queue(dispatch_queue_t dq DISPATCH_UNUSED,
 139                 const char* str DISPATCH_UNUSED) {}
 140 #endif
 141
 142 size_t dispatch_queue_debug(dispatch_queue_t dq, char* buf, size_t bufsiz);
 143 size_t _dispatch_queue_debug_attr(dispatch_queue_t dq, char* buf,
 144                 size_t bufsiz);
 145
 146 #define DISPATCH_QUEUE_QOS_COUNT 6
 147 #define DISPATCH_ROOT_QUEUE_COUNT (DISPATCH_QUEUE_QOS_COUNT * 2)
 148
 149 // must be in lowest to highest qos order (as encoded in pthread_priority_t)
 150 // overcommit qos index values need bit 1 set
 151 enum {
 152         DISPATCH_ROOT_QUEUE_IDX_MAINTENANCE_QOS = 0,
 153         DISPATCH_ROOT_QUEUE_IDX_MAINTENANCE_QOS_OVERCOMMIT,
 154         DISPATCH_ROOT_QUEUE_IDX_BACKGROUND_QOS,
 155         DISPATCH_ROOT_QUEUE_IDX_BACKGROUND_QOS_OVERCOMMIT,
 156         DISPATCH_ROOT_QUEUE_IDX_UTILITY_QOS,
 157         DISPATCH_ROOT_QUEUE_IDX_UTILITY_QOS_OVERCOMMIT,
 158         DISPATCH_ROOT_QUEUE_IDX_DEFAULT_QOS,
 159         DISPATCH_ROOT_QUEUE_IDX_DEFAULT_QOS_OVERCOMMIT,
 160         DISPATCH_ROOT_QUEUE_IDX_USER_INITIATED_QOS,
 161         DISPATCH_ROOT_QUEUE_IDX_USER_INITIATED_QOS_OVERCOMMIT,
 162         DISPATCH_ROOT_QUEUE_IDX_USER_INTERACTIVE_QOS,
 163         DISPATCH_ROOT_QUEUE_IDX_USER_INTERACTIVE_QOS_OVERCOMMIT,
 164 };
 165
 166 extern unsigned long volatile _dispatch_queue_serial_numbers;
 167 extern struct dispatch_queue_s _dispatch_root_queues[];
 168 extern struct dispatch_queue_s _dispatch_mgr_q;
 169
 170 #if HAVE_PTHREAD_WORKQUEUE_QOS
 171 extern pthread_priority_t _dispatch_background_priority;
 172 extern pthread_priority_t _dispatch_user_initiated_priority;
 173 #endif
 174
 175 #pragma mark -
 176 #pragma mark dispatch_queue_attr_t
 177
 178 DISPATCH_CLASS_DECL(queue_attr);
 179 struct dispatch_queue_attr_s {
 180         DISPATCH_STRUCT_HEADER(queue_attr);
 181         qos_class_t dqa_qos_class;
 182         int dqa_relative_priority;
 183         unsigned int dqa_overcommit:1, dqa_concurrent:1;
 184 };
 185
 186 enum {
 187         DQA_INDEX_NON_OVERCOMMIT = 0,
 188         DQA_INDEX_OVERCOMMIT,
 189 };
 190
 191 enum {
 192         DQA_INDEX_CONCURRENT = 0,
 193         DQA_INDEX_SERIAL,
 194 };
 195
 196 #define DISPATCH_QUEUE_ATTR_PRIO_COUNT (1 - QOS_MIN_RELATIVE_PRIORITY)
 197
 198 typedef enum {
 199         DQA_INDEX_QOS_CLASS_UNSPECIFIED = 0,
 200         DQA_INDEX_QOS_CLASS_MAINTENANCE,
 201         DQA_INDEX_QOS_CLASS_BACKGROUND,
 202         DQA_INDEX_QOS_CLASS_UTILITY,
 203         DQA_INDEX_QOS_CLASS_DEFAULT,
 204         DQA_INDEX_QOS_CLASS_USER_INITIATED,
 205         DQA_INDEX_QOS_CLASS_USER_INTERACTIVE,
 206 } _dispatch_queue_attr_index_qos_class_t;
 207
 208 extern const struct dispatch_queue_attr_s _dispatch_queue_attrs[]
 209                 [DISPATCH_QUEUE_ATTR_PRIO_COUNT][2][2];
 210
 211 #pragma mark -
 212 #pragma mark dispatch_continuation_t
 213
 214 // If dc_vtable is less than 127, then the object is a continuation.
 215 // Otherwise, the object has a private layout and memory management rules. The
 216 // layout until after 'do_next' must align with normal objects.
 217 #if __LP64__
 218 #define DISPATCH_CONTINUATION_HEADER(x) \
 219         const void *do_vtable; \
 220         union { \
 221                 pthread_priority_t dc_priority; \
 222                 int dc_cache_cnt; \
 223                 uintptr_t dc_pad; \
 224         }; \
 225         struct dispatch_##x##_s *volatile do_next; \
 226         struct voucher_s *dc_voucher; \
 227         dispatch_function_t dc_func; \
 228         void *dc_ctxt; \
 229         void *dc_data; \
 230         void *dc_other;
 231 #define _DISPATCH_SIZEOF_PTR 8
 232 #else
 233 #define DISPATCH_CONTINUATION_HEADER(x) \
 234         const void *do_vtable; \
 235         union { \
 236                 pthread_priority_t dc_priority; \
 237                 int dc_cache_cnt; \
 238                 uintptr_t dc_pad; \
 239         }; \
 240         struct voucher_s *dc_voucher; \
 241         struct dispatch_##x##_s *volatile do_next; \
 242         dispatch_function_t dc_func; \
 243         void *dc_ctxt; \
 244         void *dc_data; \
 245         void *dc_other;
 246 #define _DISPATCH_SIZEOF_PTR 4
 247 #endif
 248 #define _DISPATCH_CONTINUATION_PTRS 8
 249 #if DISPATCH_HW_CONFIG_UP
 250 // UP devices don't contend on continuations so we don't need to force them to
 251 // occupy a whole cacheline (which is intended to avoid contention)
 252 #define DISPATCH_CONTINUATION_SIZE \
 253                 (_DISPATCH_CONTINUATION_PTRS * _DISPATCH_SIZEOF_PTR)
 254 #else
 255 #define DISPATCH_CONTINUATION_SIZE  ROUND_UP_TO_CACHELINE_SIZE( \
 256                 (_DISPATCH_CONTINUATION_PTRS * _DISPATCH_SIZEOF_PTR))
 257 #endif
 258 #define ROUND_UP_TO_CONTINUATION_SIZE(x) \
 259                 (((x) + (DISPATCH_CONTINUATION_SIZE - 1u)) & \
 260                 ~(DISPATCH_CONTINUATION_SIZE - 1u))
 261
 262 #define DISPATCH_OBJ_ASYNC_BIT          0x1
 263 #define DISPATCH_OBJ_BARRIER_BIT        0x2
 264 #define DISPATCH_OBJ_GROUP_BIT          0x4
 265 #define DISPATCH_OBJ_SYNC_SLOW_BIT      0x8
 266 #define DISPATCH_OBJ_BLOCK_RELEASE_BIT 0x10
 267 #define DISPATCH_OBJ_CTXT_FETCH_BIT 0x20
 268 #define DISPATCH_OBJ_HAS_VOUCHER_BIT 0x80
 269 // vtables are pointers far away from the low page in memory
 270 #define DISPATCH_OBJ_IS_VTABLE(x) ((unsigned long)(x)->do_vtable > 0xfful)
 271
 272 struct dispatch_continuation_s {
 273         DISPATCH_CONTINUATION_HEADER(continuation);
 274 };
 275 typedef struct dispatch_continuation_s *dispatch_continuation_t;
 276
 277 #ifndef DISPATCH_CONTINUATION_CACHE_LIMIT
 278 #if TARGET_OS_EMBEDDED
 279 #define DISPATCH_CONTINUATION_CACHE_LIMIT 112 // one 256k heap for 64 threads
 280 #define DISPATCH_CONTINUATION_CACHE_LIMIT_MEMORYSTATUS_PRESSURE_WARN 16
 281 #else
 282 #define DISPATCH_CONTINUATION_CACHE_LIMIT 65536
 283 #define DISPATCH_CONTINUATION_CACHE_LIMIT_MEMORYSTATUS_PRESSURE_WARN 128
 284 #endif
 285 #endif
 286
 287 dispatch_continuation_t _dispatch_continuation_alloc_from_heap(void);
 288 void _dispatch_continuation_free_to_heap(dispatch_continuation_t c);
 289
 290 #if DISPATCH_USE_MEMORYSTATUS_SOURCE
 291 extern int _dispatch_continuation_cache_limit;
 292 void _dispatch_continuation_free_to_cache_limit(dispatch_continuation_t c);
 293 #else
 294 #define _dispatch_continuation_cache_limit DISPATCH_CONTINUATION_CACHE_LIMIT
 295 #define _dispatch_continuation_free_to_cache_limit(c) \
 296                 _dispatch_continuation_free_to_heap(c)
 297 #endif
 298
 299 #pragma mark -
 300 #pragma mark dispatch_apply_t
 301
 302 struct dispatch_apply_s {
 303         size_t volatile da_index, da_todo;
 304         size_t da_iterations, da_nested;
 305         dispatch_continuation_t da_dc;
 306         _dispatch_thread_semaphore_t da_sema;
 307         uint32_t da_thr_cnt;
 308 };
 309 typedef struct dispatch_apply_s *dispatch_apply_t;
 310
 311 #pragma mark -
 312 #pragma mark dispatch_block_t
 313
 314 #ifdef __BLOCKS__
 315
 316 #define DISPATCH_BLOCK_API_MASK (0x80u - 1)
 317 #define DISPATCH_BLOCK_HAS_VOUCHER (1u << 31)
 318 #define DISPATCH_BLOCK_HAS_PRIORITY (1u << 30)
 319
 320 struct dispatch_block_private_data_s {
 321         unsigned long dbpd_magic;
 322         dispatch_block_flags_t dbpd_flags;
 323         unsigned int volatile dbpd_atomic_flags;
 324         int volatile dbpd_performed;
 325         pthread_priority_t dbpd_priority;
 326         voucher_t dbpd_voucher;
 327         dispatch_block_t dbpd_block;
 328         struct dispatch_semaphore_s dbpd_group;
 329         dispatch_queue_t volatile dbpd_queue;
 330         mach_port_t dbpd_thread;
 331 };
 332 typedef struct dispatch_block_private_data_s *dispatch_block_private_data_t;
 333
 334 // dbpd_atomic_flags bits
 335 #define DBF_CANCELED 1u // block has been cancelled
 336 #define DBF_WAITING 2u // dispatch_block_wait has begun
 337 #define DBF_WAITED 4u // dispatch_block_wait has finished without timeout
 338 #define DBF_PERFORM 8u // dispatch_block_perform: don't group_leave
 339
 340 #define DISPATCH_BLOCK_PRIVATE_DATA_MAGIC 0xD159B10C // 0xDISPatch_BLOCk
 341
 342 #define DISPATCH_BLOCK_PRIVATE_DATA_INITIALIZER(flags, voucher, prio, block) \
 343                 { \
 344                         .dbpd_magic = DISPATCH_BLOCK_PRIVATE_DATA_MAGIC, \
 345                         .dbpd_flags = (flags), \
 346                         .dbpd_priority = (prio), \
 347                         .dbpd_voucher = (voucher), \
 348                         .dbpd_block = (block), \
 349                         .dbpd_group = DISPATCH_GROUP_INITIALIZER(1), \
 350                 }
 351
 352 dispatch_block_t _dispatch_block_create(dispatch_block_flags_t flags,
 353                 voucher_t voucher, pthread_priority_t priority, dispatch_block_t block);
 354 void _dispatch_block_invoke(const struct dispatch_block_private_data_s *dbcpd);
 355
 356 #endif /* __BLOCKS__ */
 357
 358 #endif